From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E5DA7CA5FD4 for ; Fri, 2 Oct 2026 10:04:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E95856B00AA; Fri, 2 Oct 2026 06:04:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E6D1E6B00B5; Fri, 2 Oct 2026 06:04:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D83A66B00B8; Fri, 2 Oct 2026 06:04:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id B299D6B00AA for ; Fri, 2 Oct 2026 06:04:36 -0400 (EDT) Received: from smtpin03.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 494F91A065D for ; Fri, 2 Oct 2026 10:04:36 +0000 (UTC) X-FDA: 85277251752.03.9119322 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf24.hostedemail.com (Postfix) with ESMTP id 916EE180011 for ; Fri, 2 Oct 2026 10:04:34 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=mVdO1SRO; spf=pass (imf24.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1790935474; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=OYncI7yMFVGEZt4HudN8D2fnyBtTKnCcRE5C8VrmBO4=; b=ieMvmHFCNEuWOExx80VsgN78BXq2MOwKlF7isA/LHAtcvQNCIhV5iInYT38c32HGtxJvi6 UzuQueVRYalingp55U+GAIDtzCIxGSOpbELQRh1JakPsfRIUXNrKiPJNBmfLvchBbUdomE SYdNWCX7OnToVtSEWTrL2N2IB1Wjpzo= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1790935474; b=HZ4m4vHVamKsUnPRAIP51G1xU0zjNyvoXlMu5vWbhLeBy3pecVWQRIUHqnamXrJB50W+2b 6RMP/WPao3HbOahNVH+QExn9G7nc5K3OkGTQVlLm0k4XluEBiwppbb60z3Yq7GqE6ZemfK qDHM/RX+EU4olJzvxT1JNQ8q7d22Lms= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=mVdO1SRO; spf=pass (imf24.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 84E3760A70; Fri, 2 Oct 2026 10:04:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5FDF21F000FF; Fri, 2 Oct 2026 10:04:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790935473; bh=OYncI7yMFVGEZt4HudN8D2fnyBtTKnCcRE5C8VrmBO4=; h=Date:Subject:From:To:Cc:References:In-Reply-To; b=mVdO1SRO4s2CqWoO+/E8Y60Ac/d7QlKMYCOyu0BWv03NeoVC13hlqDo72y+vp210w CWrLh1Pw0WKNCXHk3o+3xRUbRwy7lZ4jOV7Jg+HNYxLpM0psfLfRd4ahLO5ugeSRho fkdIJv9HTYOS0/yXLehuAQshDjTFBd6BMjnfrGmJjFpN+pxvUWtfc4zVQaT0ecczNg uFDUFeg+I47s5zu2Gc9XTPNNpzmzP5xLQ+tEf5uVMT+lsLzmosSVdQLQF3TkJhJzmL cpxzENdCJWGWtNl8bwd+PrhAwmFG48VftYC5/k1U0QJKM/nusEoqXnb+Pto2MaSNuI wieX7kW2lzwSw== Message-ID: <9d43234f-93cb-4c86-a2a6-a3cdebf48f3b@kernel.org> Date: Fri, 2 Oct 2026 12:04:27 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: don't ioremap COWed anon pages in generic_access_phys() From: "David Hildenbrand (Arm)" To: "Lorenzo Stoakes (ARM)" Cc: Nguyen Ngoc Thang , akpm@linux-foundation.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, peterx@redhat.com, dave.hansen@linux.intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, syzbot+49b1021becba70c1f3f6@syzkaller.appspotmail.com References: <699ae98c.050a0220.340abe.0d31.GAE@google.com> <20261001152524.171115-1-ngocthang2710.1999@gmail.com> <32fe40e2-854a-47ec-9d95-93e23f9a7af4@kernel.org> Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 916EE180011 X-Stat-Signature: qb4yd5fz8chk6j8b6o1he4ofdxjufh19 X-Rspam-User: X-HE-Tag: 1790935474-367294 X-HE-Meta: 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 XOWwjpRT NZMoQKTCrFOsnfPrbcfjluwIoTcMH1EjV65L0tcEUS6uo5XR9L7mmGo/59W/2WkOTw6JKrW9A0z43PoQMbUrD6mNYD/7VHjhM3DcP0ZEzRUhPnOElPvH7D5p3so15G40r57qQfHOouPx0C7icKSd023Fjvewfxbd0w1rIQVWjRYzRv1qQNmRIqhqVrpqpX9RrZxAiPIC3UWj7hKpAIw8K3G8Y/low6WxjUY3vPAq/OLxfNnjH5acwCVKm1hfy9nVm5mZN9XLvupyEJ2FjDM5i6XjffY1hkao3cQCVcrGwlpUognN02LdHFnJlrnZnG3CygChgeFYbWgKiy3mL3VhfS24ZdkL3/05lwt8hrVor/smBb89HdBqsgzcGtDI78gbLOzhZ6Z1yEk5xUYy6Bu5cgs/WLklJAy1jqtF4Vt7ZXEWT+U60YuJ2gR01dVn8jJEbnOkesWVwpTCsyfNxuRxU2Yx678jDvQiH7VXDwdEfCrTJq0Q= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 10/2/26 12:02, David Hildenbrand (Arm) wrote: > On 10/2/26 10:38, Lorenzo Stoakes (ARM) wrote: >> On Thu, Oct 01, 2026 at 10:22:29PM +0200, David Hildenbrand (Arm) wrote: >>> >> >> Sorry to say this looks schlopped. >> >> This guy has sent 10 series across 6 subsystems over ~21 hrs: >> >> https://lore.kernel.org/all/?q=f%3Angocthang2710.1999%40gmail.com >> >> Nguyen - please do not flood the kernel with patches, and please use the >> Assisted-by tag for generated content. >> >> The original code you submitted is really not great even if the issue may >> be valid. >> >> So I'd say somebody from the core team should take over this if we want to >> come up with a patch. > > Yes, I'll take care of it. > > [...] >>> >>> Signed-off-by: David Hildenbrand (Arm) >> >> This looks reasonable but I hate that we have 'special' CoW overrides like >> this :) > > After sending this yesterday, I concluded that we can do this cleaner: just have > > bool normal_page; > > (naming suggestions?) > > that express that this is something refcounted with a struct page, like > documented for vm_normal_page(). Hmm, have to think about that once more, regarding VM_IO and if there are some cases that would actually have to work in generic_access_phys(). -- Cheers, David